H NMR. It was first used for synthesis of azlactones via Erlenmeyer synthesis from aromatic aldehydes and hippuric acid under solvent-free conditions. It was found that aldehyde substituents play an important role in these reactions. Better conversions and therefore higher isolated yields were observed when electron-withdrawing groups EWG- were present in the aromatic aldehyde. Opposite results were shown when electron-donating groups EDG- were present in the aromatic aldehyde. However, azlactones were obtained in moderate to high yields.